Electric switch



Dec. 16, 1952 A. e. KLlNG ETAL ELECTRIC SWITCH Filed June 2, 1950 2 SHEETS-SHEET l INVENTORS ARNOLD 6. Kune Rosam- L. WOLFF BY AT'roaneY Patented Dec. 16, 1952 ELECTRIC SWITCH Arnold G. Kling and Robert L. Wolff, Milwaukee, Wis., assignors to Globe-Union Inc., Milwaukee, Wis., a corporation of Delaware Application June 2, 1950, Serial No. 165,682

5 Claims.

This invention relates to improvements in electrical switches and particularly to such switches of the quick-make and slow-break type for alterhating current or direct current use which are operated by reciprocal angular movement of the control shaft of a variable resistor or other component with which such switches are associated.

The opening and closing of the switch must be accomplished through a minimum of angular movement of the control shaft. One way of ac complishing this is to have the contacts open and close in a lineal path which is substantially parallel with the axis of rotation of the control shaft and to effect such movement by means of a cam mechanism which produces such relative lineal movement upon angular movement of the shaft. In presently used switches of this type the camming surface is relatively fixed and a follower is moved on such surface by a control member which continuously rotates with the control shaft. One disadvantage of such construction is the continuous torsional drag on the operating shaft. Another disadvantage arises from the required excess angular movement of the control shaft to effectuate the operation of the contacts.

A further disadvantage is the necessity of proper alinement between the switch control element and the control shaft upon assembly of the combined unit. While a spring toggle switch construction appears to eliminate some of these disadvantages, it also has disadvantages one of which is the troublesome sticking in either opener closed.

positions.

It is an object of this invention, therefore, to provide an electrical switch of the quick make and slow break type which may be operated by the angular movement of the controlz'shaft of an associate component without continued tortional drag on such shaft, and with a minimum of required switch-actuating angular movement thereof, which switch may be manufactured by low cost production processes and readily and simply assembled with a variable resistor or the like.

Another object of this invention is to provide an electric switch of the quick make and slow break type which has a compact unitary structure eliminating adverse effect from tolerance pile-ups in individual subassemblies.

These objects are obtained by mounting the s control member so that it rotates aboutan axis spaced from the axis of the control shaft and providing a momentary interlock between the control shaft and the switch control member.

This eliminates continuous tortional drag on the c control shaft and permits the use of a relatively long lever on the control shaft whichtemporarily engages with a relatively short lever on the control member. Thus a minimum of angular movement of the control shaft effectuates the operation of the switch. A finger on the relatively long lever moves into momentary contact with a jaw on the relatively short lever of the switch control member to shift such member between off{ and onv position. At other positions of the control shaft the finger is free of contact with such jaw. Hence, in assembly of the unit, no special alinement of the control member and control shaft is needed The novel features, which are considered characteristic of the invention, are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and its method of operation, together with additional objects and advantages thereof, will best be understood from the following description of a specific embodiment when read in connection with the accompanying drawings, in which:

Fig. 1 is a view partly in elevation and partly in cross section on the line I--l of Fig. 2 of va switch embodying the present invention associated with a variable resistor and in the off position;

Fig. 2 is a sectional view taken on line 2-2 of Fig. 1 with the cover of the resistor removed for sake of clarity in illustration;

Fig. 3 is a view partly in elevation and partly in section on the line 3--3 of Fig. 4 similar to the view of Fig. l with the switch in on position;

Fig. 4 is a fragmentary sectional view similar to the View of Fig. 2 showing the switch in on position; and I Fig. 5 is a fragmentary sectional view taken on the arcuate line 5--5 of Fig. 4.

Referring to the drawings by reference numerals, the switch generally indicated at In is mounted on the back of a control component such as the variable resistor 12. The unit so formed may be mounted on a panel in the wellknown manner. A control shaft [4 is rotatably mounted in the resistor l2. A finger l6 projects rearwardly from a relatively long lever l8 mounted on the inner end of such shaft. The finger 16 moves in an arcuate path as the control shaft !4 is rotated in the adjustment of the resistor and momentarily engages the jaw 64 of the switch control member 58 in the manner hereinafter described to operate such member and thus actuate the switch from off to on position and from on to off position by utilizing only a relatively small part of the permissible angular movement of the control shaft. During further movement of the shaft l4 of finger i6 is disengaged from the jaw and the resistor can be adjusted without actuation of any of the switch elements. v v

The switch It! is mounted in an insulating housing 20 which provides the support for the various switch elements. and 24 are mounted on pads within the housing 20 and have shanks projecting through the rear wall of the housing and connected to terminals 26 in the customary manner.

which are secured to a pad in housing 2|] by rivets 36, the latter being connected to terminals 36 in the well-known manner. The switch thus shown and described is of the double pole type. If it is desired to make a single pole switch, the spring arms 32 and 34 may be made in one piece and a single centrally located rivet used in place of the two rivets 36 to mount such single piece in. the housing. In addition to such change one of the movable contacts 28 or 36 and its associated stationary contact 22 or 24 and terminal 26 are omitted. In either case, projections 40 on the spring arms aid the rivets in positioning and holding such arms within the housing 26. The spring arms 32 and 34- are normally resiliently biased to urge the movable contacts 28 and 36 into engagement with the stationary contacts 22 and 24. The movement of such contacts is along a lineal path substantially parallel withthe axis of rotation of the shaft [4.

Direct control of the movable contacts is accomplished by an insulator plate or contact actuator 42 loosely positioned within the housing 20 between the rear wall thereof and the contact-carrying arms 32 and 34. This plate has peripheral notches 44 and 46 to provide room for the contacts 28 and 36 to engage the stationary contacts 22 and 24 when the plate 42 is positioned in its switch on position adjacent the rear wall of the housing (see Fig. 3). The plate is urged toward this position by the spring pressure of arms 32 and 34. When such plate is moved or tilted away from the rear wall of the housing (left as viewed in Figs. 1 and 3) it will engage the ends of spring arms 32 and 34 and carry the contacts 28 and 30 out of contact with fixed contacts 22 and 24. This is the off position of the switch.

Such movement of the plate 42 is accomplished by camming means. The rear wall of the housing has a camming surface 48 which slopes between 9, high seat 56 and a low seat 52 spaced as shown in detail in Fig. 5. It is desirable to provide a circular depression 54 in the high seat 50 into which the cam follower drops to cause an audible and tactile signal. The camming surface 48 and low seat 52 may be duplicated on the opposite side (right as viewed in Figs. 2, 4, and of the high surface 50 so that the switching action may be accomplished at either end of the rotational travel of the control shaft I4. The pitch of the camming surface 48 is suiiicient to cause the contact actuator to have enough lateral movement to fully separate the contacts upon slight angular movement of the cam follower. In this embodiment the cam follower 56 is a steel ball which is placed between the plate 42 and the fixed camming surface. As the ball is moved from the depression 54 in high seat 50 (switch off position) it rides down the camming sur- Stationary contacts 22.

Movable contacts. 28 and 30 are mounted on spring arms 32 and. 34

face 48 to the low seat 52 (switch "on position). During this movement the plate 42 swings toward the rear wall and the contacts engage in a relatively quick fashion. While in some respects a ball performs the function of a cam follower satisfactorily, it is not essential that the cam. follower take the shape of a .ball. Any member which: will retain its desired size: and will readily slide up and down the sloping surface 48 will perform satisfactorily as a cam follower. The movement of the cam follower 56 is caused by a control member 58. This member is rotatably mounted on a pin 60 secured to the housing 20. and itsaxis of. rotation is substantially paral-- 'lel to but spaced from the axis of rotation of the control shaft [4. The control member 58 has one jaw 62 which. receives the cam follower to slidably engage it and move it along the camming path when the control member 58 is rotated about its axis. Such control member has a second jaw 64 which is positioned laterally of the housing 20' toward the resistor I 2 to slidably momentarily engage the finger I6. In this par-- ticular embodiment the housing 26' is so designed that in the off position of the switch the cam follower 56 is in substantial alinement wtih the common plane of the axis of shaft l4 and pin 60. As so arranged it is desirable to angularly offset the jaw 64 with respect to the. jaw 62. By positioning the left-hand tooth of jaw 64 counter-clockwise from jaw 62 (as viewed in Fig. 2) the amount of clockwise. angular movement of the control member 58 caused by a. predetermined angular movement of' the finger [Bis decreased from the amount required from having jaws 64 and 62 in al'inement. Thus the advantage obtained by spacing the axis of rotation of the control shaft and control member is further increased. The distance from the axis of the shaft H to the finger I6 is greater than the distance from the axis of pivot to jaw 64 and the latter distance is less than the distance from the axis of pivot 60' to jaw 62. These distances are the measure of the levers by which the finger and jaws are supported and it is an important aspect of this invention that a large mechanical advantage differential is obtained in an overall relatively small space by this arrangement of levers. The size of the switch body may thus be reduced and only a small portion of the complete rotation of the control shaft I4 is required to operate the switch.

While the spring tension in contact arms 32 and 34 is sufficient to continually urge the contact actuator 42 into engagement with the cam follower 56, such tension is not applicable once contact has been made. In the on position, therefore, the actuator 42 and cam follower 56 would be loose within the housing. This might result in a noisy condition or improper displacement of the cam follower. Such may be avoided by the addition of springs 66 and 68 formed from the same material as the spring arms 32 and 34. These springs are inherently biased so that they continue to apply a lateral pressure against the contact actuator 42 even after the motion of the spring arms 32 and 34 has been arrested by the engagement between the movable and stationary contacts. Thus sufficient tension is always maintained between the contact actuator 42 and the cam follower 56 thereby eliminating any loose fit.

In order to properly assemble the switch ID on back of the resistor l2, the rear of the casing of the resistor is provided with an opening sufficiently large to receive the projecting end of the control member 58. It is also advantageous to provide recesses 10 in the peripheral portions of the casing 20 which receive projections 12 on the casing of the resistor I! to angularly locate the switch ID with respect to the resistor l2. In assembling the switch to the resistor, it is preferable to move the control member 58 to the on position, as shown in Fig. 3, (in which it will stay while being handled) and the control shaft to any position other than full off position. Thusly arranged there is no need for any accurate alinement between the finger l6 and the jaws 64 in order to have the switch and the resistor fit together properly. Such an assembly can also be easily made without trouble provided the switch is in off position and the control shaft in off position. Any type of clamping member may be used to hold the switch housing to the resistor. One method is to provide straps on the housing of the resistor 12 which fit in recesses along the sides of the housing 20 and are bent over the rear wall of the housing 28.

With the device assembled as hereinbefore described, and with the switch and resistor in off position, it is only necessary to rotate the control shaft I4 an angular amount of approximately twenty-five degrees in order to rotate'the control member 58 an angular amount of approximately fifty-three degrees. The latter movement is sufficient to actuate the switch from off to on position, and vice versa. Such movement, directly controlled by the shaft [4, causes contact to be quickly made. After the switch has been moved to open position the rotation of the control shaft l4 may be continued to adjust the resistor or other component without any rotational drag imposed on such shaft by continued connection with switch elements. When the control shaft is moved back toward off position the finger [6 will engage jaw 64 and approximately the last twenty-five degrees or so of the rotation of such shaft will cause the carrier 58 to rotate back to the position of Fig. 2 causing the contacts to be slowly opened, thus allowing a change of voltage through zero with alternating current during such breaking. There is enough lost motion in the actuator 42 to have the switch produce an audible and tactile signal as the cam follower moves into final off or final on position. However, the contact has been broken before such lost motion takes effect and it therefore does not produce any snap action.

Although only one embodiment of the invention is shown and described herein, it will be understood that this application is intended to cover such changes or modifications as come within the spirit of the invention or scope of the fo lowing claims.

We claim:

ing a body with a fixed contact and a movable contact resiliently biased to closed position and a cam and cam follower for moving said movable contact to open position upon arcuate movement of said cam follower, means for arcuately moving said cam follower comprising a control member mounted on said body and pivoting about an axis substantially offset from the center of said body,

member having a first portion in sliding contact with said cam follower to impart movement thereto as said member is swung about said axis, and a second portion laterally ofiset from said first portion and projecting beyond said contacts within the peripheral confines of said body and adapted to be engaged for the operation of said switch.

2. An electric switch of the rotary type com- I prising a housing with a rear wall and sides defining a recess, a fixed contact, a movable contact, an insulating contact actuator movable laterally between said rear wall and said movable contact to actuate said movable contact, a cam and cam follower in continuous engagement with said actuator for moving said actuator upon movement of said cam follower along said cam, a control member for said follower, and a pin fixed to said rear wall, said member being pivoted on said pin and swingable about said pin to move said cam follower along said cam, said member having a rearward jaw for engaging said cam follower and a forward jaw by which said member is swung, said forward jaw being spaced forwardly of said contacts but within the confines of the sides of said housing.

3. A switch as claimed in claim 2 in which there is spring means biasing said contact actuator toward engagement with said follower while said contacts are closed.

4. A switch as claimed in claim 2 in which said forward jaw is closer to the axis of said pin than said rearward jaw to provide greater angular movement for said rearward jaw upon angular movement of said forward jaw.

5. A switch as claimed in claim 2 in which said forward jaw is closer to the axis of said pin than said rearward jaw and said forward jaw is angularly offset with respect to said rearward jaw to provide greater angular movement for said rearward jaw upon angular movement of said forward aw.

ARNOLD G. KLING. ROBERT L. WOLFE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,930,980 Maibohm Oct. 17, 1933 2,231,218 Palmer Feb. 11, 1941 2,488,778 Meuer Nov. 22, 1949 

